Making it easy
You need a sprint device phone, basically a phone with a Sprint logo. Then just walk into a store or call in and have them run credit and choose a plan.
you can go to sprint.com and browse the selection of phones and pick the one you like. once you do that you can enter your information for a credit check and begin the process to start service with sprint. If you would like to see the phones first in person then i suggest you go to a local store and they can start the process of getting you set up. if you need to find the nearest store to you, go to sprint.com and input your zipcode and it will find the closest stores to you